The steering and stability characteristics of motorcycles, bicycles and other similar types of vehicles can be varied and altered in a number of different ways. Altering the front wheel assembly rake and trail angles can change the steering and stability characteristics of a motorcycle. The rake angle is defined as the angle which the steering axis of the front wheel assembly of the motorcycle (often called the “neck” of the motorcycle frame) has relative to an imaginary vertical axis or plane. Thus, if an imaginary vertical plane is passed through the steering head assembly of a motorcycle, the rake angle is that angle formed between such plane and steering axis of the front wheel assembly. The horizontal distance of the forward wheel's axle from a pre-defined measure is generally referred to as a motorcycle's trail. The trail can also be described as the distance defined by a vertical line from the axle of the front tire to the ground and the intersect of the line extending through the steering axis and the ground.
Variations in the rake and trail angle of a motorcycle will provide different ride and steering characteristics. Motorcycle riders and builders often extend the rake angle to obtain a desired look and desired performance. Motorcycle rake and trail angles are precise measurements that depend greatly on, and are impacted by, the size of the front wheel of the motorcycle. Thus, if a rider or builder desires to change the size of the front wheel, it is often necessary or desirable to also alter the rake angle of the motorcycle to achieve the desired level of performance, stability, and safety. Various methods may be employed to extend the rake angle, ranging from permanent modifications to the motorcycle frame, to raked triple trees, to adjustable kits.
Various methods of adjusting the front assembly of a motorcycle, including extending the fork angle are disclosed in U.S. Pat. Nos. 3,866,946, 4,082,307, 5,967,538, 4,565,382, 7,111,861, and 7,438,306.
While these kits allow for adjustment of the fork rake associated with a motorcycle, there is a need for a simple apparatus and method that can easily, reliably, accurately, and permanently be applied to a stock motorcycle to obtain a desired altered rake angle.